1.4 - enzymes Flashcards
what is the metabolic pathway an anabolic reaction?
building up molecules e.g. protein synthesis
what is the metabolic pathway and catabolic reaction?
breaking molecules down e.g. digestion
metabolic pathways are controlled by…?
enzymes
the products of one enzyme-controlled reaction become..?
reactants in the next
what properties do enzymes exceed?
- speed up reactions
- not used up
- they are not changed
- they catalyse many reactions per second
how would you describe an enzyme?
a protein with a tertiary structure that form a globular shape with hydrophilic R groups on the outside.
are enzymes soluble?
yes.
what determines the bonds the amino acids make with each other in the protein - enzyme?
the elects in the R groups
what holds the enzyme in its tertiary form?
hydrogen bonds, disulphide bonds and ionic bonds.
what are the 3 sites called where the enzymes act?
- extracellular
- intracellular, in solution
- intracellular, membrane bound
describe the lock and key theory.
unique shaped active site catalyses the one type of reaction
define a enzyme - substrate complex.
a structure formed during an enzyme catalysed reaction where the the substrate and enzyme bind temporarily
define activation energy.
the minimum energy that must be put into a chemical system for a reaction to occur.
heat speeds up reactions in non-living systems however what would happen if you increased to the temperature to 40 degrees in living organisms?
cause irreversible damage to proteins and they denature
what do enzymes do to the activation energy? what does this allow?
lowers it , reactions to occur at lower temperatures
in a graph showing the formation of product overtime why does it plateau?
all the substrate has been used so no more product can be formed
how does a change in temperature increase the rate of reaction?
INCREASED temperatures means more kinetic energise the enzyme and substrate collide more often.
what happens if the temperature is increased to 40+ degrees?
increasing vibrations break the hydrogen bonds changing the structure of the enzyme meaning the substrate does no longer fit - enzyme denatures.
what happens to the enzymes at very low temperatures?
inactivated although the shape is unchanged so if the temperatures were raised again they enzyme would work again.
what can small pH do to the enzymes?
cause reversible changes and reduce activity
what can a high pH do to a enzyme?
denature enzymes
the rate of reaction increases as…?
the substrate concentration increases
why is substrate concentration a limiting factor?
it controls the rate of reaction
when all the active sites are full the enzyme is…?
saturated
